[clang-tools-extra] added option `google-readability-namespace-comments.AllowNoNamespaceComments` (PR #124265)

[Baranov Victor via cfe-commits]

vbvictor wrote:

@thorsten-klein, gentle ping, do you still wish to work on this check?
21th LLVM release will be soon, If you wish to have your changes in the upcoming release please rebase on main and fix issues suggested by HerrCai0907.

https://github.com/llvm/llvm-project/pull/124265